A) Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a vertical alignment type liquid crystal display device.
B) Description of the Related Art
Alignment directions of liquid crystal molecules of a liquid crystal display device (particularly a vertical alignment type liquid crystal display device) are controlled by a rubbing process for alignment films to improve the image quality. The present inventors and others have proposed in JP-A-2005-234254 a liquid crystal display device having a uniform pretilt angle and no rubbing flaws after a rubbing process for an organic polymer material thin film such as polyimide formed on the substrates, and its manufacture method.
An alignment film of a liquid crystal display device is charged with static electricity by a rubbing process. As this static electricity is discharged, a liquid crystal alignment function of the alignment film is damaged and an alignment defect is formed. This liquid crystal display device is a defective product having a localized optical hole (in this specification, this localized optical hole is called an alignment hole). The alignment hole forms a white dot in normally black display, and a black dot in normally white display.
JP-A-HEI-7-318879 has proposed a method of preventing alignment defects to be caused by static electricity discharge by externally connecting the electrodes to make them have the same potential.